Nuclear import of proteins and nucleic acids is central to many cellular processes and cell-pathogen interactions. Some bacteria and viruses encode specialized proteins that transport genomic DNA and RNA molecules of the invading pathogen into the host cell nucleus. One of these is the VirE2 protein of Agrobacterium. Agrobacterium elicits neoplastic growths on many plant species by transporting a single-stranded copy of the bacterial transferred DNA (T-DNA) into the plant cell nucleus. VirE2 alone appears to be sufficient to transport T-DNA into the host cell nucleus. Since the T-DNA is not sequence specific, the complex between any ssDNA and VirE2 is competent for active nuclear import. M13 ssDNA and VirE2 were incubated and examined in the STEM. Both freeze-dried and stained specimens were prepared. The data from these are being analyzed to elucidate the structure of nuclear import intermediates.